This is a very narrow viewpoint, considering the majority of computing is done on touch screens now. Sometimes keyboard controls are critical, sometimes they're not, sometimes your users don't care, sometimes they do. Sometimes a pointer is a better human interface for something, sometimes a purpose built controller is, sometimes a multi touch sensitive touchpad is. I wouldn't make an FPS that was just keyboard controls and the same is true of some other types of UIs. Just measure it and be creative and empathetic to how people will use your product who aren't like you and consider the physical interactions as a part of your design space and not just the software.